homework是可数名词吗为什么

He let us off homework today.

他今天免了我们的家庭作业。

I still haven't done my geography homework.

我还没做完地理科家庭作业呢。

How long did you spend on your homework?

你做家庭作业用了多长时间？

I've got a lot of homework tonight.

我今晚有很多家庭作业要做。

Do exercise one for homework.

家庭作业做习题一。